Exploration drilling of suspected and known mineral deposits is commonly performed in the process of locating and evaluating mineral deposits. In the course of an exploration of a given geography, it is not uncommon to lay out an extensive grid pattern of drill sites, drill hundreds to thousands of mineral-sampling holes as dictated by the grid pattern, and assay the multitude of samples obtained by the sample drilling. Then, based on the assays, overlay another grid pattern and conduct a more extensive drilling of sampling holes. Of course, a likely candidate location must be first identified, often by random, sample drilling, often called "wildcat drilling." Then the evaluation of the candidate location begins with sample drilling of a wide grid pattern to identify possible minable reserves. Then, if further exploration is warranted, sample drilling on a finer grid pattern of the proven minable reserves is conducted for mine planning.
In order to perform this extensive sample drilling, access roads and drilling sites must be located and established. The cutting of access roads and surface drill sites has a very significant impact on the ecology of the surrounding geography. Site and road preparation is costly; and, where required, returning the terrain to its original condition is also costly. This is a major undertaking. Each surface drill site, for example, must have sufficient room for the drill and drill pipe, water pumps, drill rods, drilling mud, storage containers of various types, turn around for the drill rig and other vehicles. Efforts are made, therefore, to provide mobile sample drilling systems in as compact a configuration as possible, while still being capable of meeting the sample drilling requirements.
This can pose problems in that various geological structures may require that different drilling techniques be employed; and a particular drilling rig is not necessarily capable of employing the drilling technique required at a particular site. Oftentimes, a particular exploration project will require the use of more than one drilling technique over the course of the project. Consequently, a driller must have several types of drilling rigs available in order to qualify for the drilling jobs that will become available.